My interests are focused on the relationship between the metabolic and growth effects of insulin and insulin-like growth factors (IGF's). I have begun to study the role of hormones and metabolic factors such as hyperglycemia in the development of diabetic retinopathy and macro-vascular diseases. My previous publications and preliminary studies have shown that retinal capillary endothelial cells and pericytes are insulin and IGF sensitive tissues. In addition, hyperglycemia inhibited the growth of retinal capillary cells but not aortic endothelial and smooth muscle cells. In this proposal, my laboratory will biochemically characterize insulin receptors and effects on bovine retinal capillary endothelial cells, pericytes, aortic endothelial cells, and smooth muscle cells that we have cultured. These experiments could elucidate the mechanism for the differential responsiveness to insulin and IGF's between cells from retinal capillaries and large peripheral blood vessels. The inhibitory effect of hyperglycemia on the growth of retinal pericytes will be analyzed to determine its mechanism of action by using autoradiography, flow cytometer and metabolic studies using competitive inhibitors of glucose. Its effect on the growth of the endothelial cells from bovine retinal capillaries and aorta will also be studied. In addition, the effect of hyperglycemia and insulin on the function of endothelial cells from retina and aorta will be characterized to determine whether they can alter the non-thrombogenic property of these cells with respect to platelets and erythryocytes. For estimating thrombogenicity, an adhesion assay measuring the affinity of Gamma 51-chromate labeled erythryocytes for the endothelial cells will be used. Lastly, using co-cultivation techniques of growing endothelial cells and pericytes together separated only by porous membrane, important interactions between these cells can be studied. The effects of exposing cells in co-cultivation to "diabetic milieu" such as hyperglycemia may be altered differently than if the cells were grown singularly. The technique of co-cultivation can be a promising model for the study of diabetic retinopathy. In summary, I hope to define the effect of various hormones and hyperglycemia on the growth and functions of retinal capillary and aortic cells. This information will allow the designing of means to prevent or reverse diabetic retinopathy and peripheral vascular disease.